Power hand tool



May 4, 1955 R. A. E. zl-:TTERLUND 3,181,338

POWER HAND TOOL Filed July 26, 1962 2 Sheets-Sheet 1 Rw: 6.5 Zermfzlf/No 5M #MWL ATTORNEYS May: 4.- 1965 R. A. E. zETERLUND 3,181,338

PowER HAND TooL Filed July 26, 1962 2 Sheets-Sheet 2 INVENTOR. ,Qq/v5 AE rzRw/va BY ATTORNEYS United States Patent O lli POWER HAND 'lltfl Rune it.. ZE. Zetterhrnd, Abington, Pa., assigner to Standard lressed Steel Co., tenltintown, Pa., a corporation or Pennsylvania Filed July 26, i962, Ser. No. 2l2,62l d Ciaiins. tCl. '72--39l) T his invention relates to a power hand tool for installing press nuts i.e., a one piece all metal nut, usuallya lock nut, designed to attach a tapped hole to a sheet or thin section in blind applications and especially the DN l2 series press nuts produced by Standard Pressed Steel Co.

The equipment presently employed to install such fasteners are subject to many defects which render them unsuitable for many important industrial applications. Manual tools are slow and not well adapted for production line use. The existing power tools are hydraulic units `and are not readily portable yas the hoses tend to stiften when under the operating pressures employed to seat the nut and therefore hamper freedom of movement of the tool by the operator. Further, some existing tools are not spark and explosion proof and thereby cannot be used where there is a danger of explosive vapors permeatlng the atmosphere. i

Accordingly, it is the object of the present invention to readily provide a power hand tool which is easily portable and manipulatable by the operator and uses a power source commonly available in factories, repair acilities and iield installations. lt Iis a further object that the tool should also be spark free and explosion proof so that it can be safely operated in the vicinity of fuel or other explosive vapors.

These objects and advantages are achieved in accordance with the present invention by a power hand tool cornprising an anvil, a mandrel having an outer threaded end passing through a hole in the anvil, a first power system adapted to controllably impart rotational movement to the mandrel in clockwise and counter-clockwise directions, and a sec-ond power system adapted to retract the mandrel relative to the anvil.

The invention will be more readily understood by reference to the accompanying drawings in which:

FG. 1 is a schematic View showing the power hand tool and associated auxiliary equipment including the air supply, filters, pressure regulators, lubricators, supply lines, etc.

FlGS. 2 8 illustrate the various steps in the installation of a press nut.

FIG. 9 is a cross-sectional view of a power hand tool made in accordance with this invention.

FIG. 9a is a view of a portion of the tool illustrated in FG. 9 but showing the movement of the pistons of the pneumatic and hydraulic power systems during the swaging and seating of a nut.

Referring now to the series of views shown in FIGS. 2-8. in FIGURE 2, can be seen the anvil l and the mandrel 2 of an installing tool. There is also shown the internally threaded press nut 3 which is to be installed in the sheet 4. The diameter of hole 5 in the sheet 4i will accommodate the barrel portion 6 of the press nut without play. The nut is provided with a knurled flange 7 having a diameter greater than that of the barrel of the nut. A portion of the internal wall 8 of the nut is reduced in thickness. This thinned wall area must be at or slightly .beyond the blind face 9 of the worlr piece, which is not supported when the nut is first positioned in the hole 5 as in FIG. 4.

As shown in FIG. 3, the nut is threaded on the mandrel snug against the -anvilhpreferably `so that about 1 to 3 threads pass through the nut. Then, as shown in FlG. 4, the nut is inserted in the hole of the work piece. In

CII

LBS Patented May d, 1965 ICC FIG. 5 an axial load is .applied in the direction shown by the arrows to retract the mandrel 2 relative to the anvil l and start the swaging l@ in 4the recessed area 8. In FIG. 6 the swaged section ll seats on the work piece i and in FIG. 7 anvil pressure imbeds the knurl 7 in the work piece. When the knurl is fully seated flush tothe sheet, the mandrel is Unthreaded, thereby attaching a tapped hole 12, to the sheet as shown in FIG. 8.

Referring now to FIGS. l, 9 and 9a which illustrate a power hand tool incorporating the various features of the present invention. The overall configuration of the tool generally corresponds to that of an electric hand drill with a pistol grip. The tool housing assembly is divided into four zones: the header housing portion A, the tandem piston cylinder chamber portion B, the air motor housing portion C, and the body and piston hand grip D.

As can be seen in FIG. 9, the header housing portion is generally in the shape of a hollow struc-ture of circular cross section 113 proiecting out from the body of the tool. It primarily defines -a hydraulic cylinder chamber M. Within or associated with the header housing is the header piston l5 of the hydraulic power system, the threaded mandrel 2, which passes through the opening of the adjustable anvil 1t, and :a drive shaft lo which is coupled to the mandrel 2 in such a way that both parts can follow the reciprocating movements of the header piston. The mandrel and drive shaft are also mounted so that they can rotate about their axes independent of the header piston.

As shown in FIG. 9, the header piston l5 includes a hollow cylindrical barrel portion 17 attached to a cup shaped piston head lit-5. leakage of hydraulic tluid about the piston head lid is prevented by a cup packing element i9 secured to the pressure side of the piston head by the bolted sealing support ring Ztl which surrounds the barrel i7 of the header piston. The piston head is cupped on the underside to provide a positive mechanical sto-p to piston movements and also to prevent the pis-ton head from interfering with the operation of the gearing used to impart rotational movements to the drive shaft and mandrel. The outer end of the barrel of the header piston rides in a packing gland assembly in the header housing which includes a packing box 22, packing material 23 and a packing boX nut 2d to hold the packing in place.

As previously noted, the barrel 17 of the header piston is hollow. A drive shaft f6 is coaXially aligned with and runs through the hollow barrel of the header piston. The drive shaft passes through and is supported by a pair of ball bearings 25', 26 whose outer races are seated against shoulders 27 and 28 respectively within the hollow header piston shaft. The bearings are clamped in place by collars or other suitable means (e.g., the hub of the spur gear 29 and of the clutch plate 3d) which are secured to the drive shaft and bear against the opposed bearings from opposite sides urging them against their respective shoulders and thereby form an assembly which will follow reciprocating movements or" the header piston and at the same time will permit the drive shaft to rotate independent of the header piston.

The spur gear 29 which is driven by the air motor system is attached to the innermost end of the drive shaft 16. The outermost end of the drive shaft lo is provided With a positive type mechanical clutch to transmit rotary movements to the mandrel 2 by means of jaws on the clutch plate 3d engaging mating jaws of a clutch plate 3l carried by the mandrel 2. The outer end of the hollow header piston barrel is threaded to receive a retainer nut 32 which is provided with an opening through which the shaft portion 33 of the mandrel can pass with a slip fit. The various associated parts are dimensioned so that when the clutch faces 3d, 31 of the drive shaft and the mandrel are engaged, and when the retainer nut 32 is tightened, it will bear against the unengaged side D of the mandrel clutch face and will maintain the clutch engagement without regard to the position of the header piston.

The outermost end of the header housing 13 is internally threaded 34 and adapted to receive a nose nut 35. The anvil 1 is threaded 36 into an opening in the nose nut 35 and the mandrel shaft portion 33 passes through an opening in the anvil with a slip fit.

The tandem pneumatic piston cylinder chamber B (hereinafter sometimes referred to as the pneumatic cylinder chamber) is also of generally circular cross section and preferably it, as illustrated, projects out from the body of the tool housing in a direction opposite to that of the header housing. This arrangement gives better balance to the tool. A transverse wall 37 is positioned in the pneumatic cylinder chamber and divides the chamber into two coaXially aligned but separated chambers 33a and 38h'. A piston rod 39 carries two piston heads 46a and 40b arranged in tandem, one head being positioned in each of the said chambers. Suitable sealing rings, packing glands and gaskets are employed in connection with the piston heads and shafting so that air will not readily leak from chamber to chamber. The outer or lead end 41 of the piston rod 39 functions as the piston head of a hydraulic booster system whose cylinder chamber 42 is in the body of the tool housing. A packing box assembly 43 including packing 44 and a gland nut 45 effectively seals the booster piston 41 of the hydraulic power system.

At the bottom of the pistol grip there is a connection 46 for a hose 47 to supply compressed air to the pneumatic system. In the illustrated embodiment, a springloaded trigger controlled four way valve 48 (i.e., spring loaded to return the valve to and maintain the valve in a closed position) is positioned in the handle. The valve chest is connected to air passages 49, 49a, 49h, 49C and vent line 57. Passage 49 leads from the air supply connection 46 to the valve chest. Passage 49a leads from the valve chest to piston chamber 38k and also to line 4911 which, in turn leads to piston chamber 38a. Passage 49c leads from the valve chest to the piston chamber on the return side of piston 40h. Vent 57 leads from the valve chest to the atmosphere.

A selector valve 50 in the air passage portion between the air inlet 49a to the piston chamber 38b and the air inlet 49b to chamber 38a permits air to act on one or both of the piston heads 40a, 40h, as desired and thereby provides a two step control over the force which can be exerted by the pneumatic power system on the hydraulic booster system without changing the pressure of the primary air supply.

If the tandem pistons of the pneumatic system are made with differing effective work areas, and if a three position selector valve and suitably modified air passages are employed, it is possible to introduce air into either chamber independently or into both chambers simultaneously and thereby readily provide three different stages of force which can be applied to therhydraulic booster system without changing the pressure of primary air supply.

When the tool is connected to the primary air supply system 51 (FIG. l) and the valve 48 is opened to allow air to pass through line 49a and enter either or both of the pneumatic piston. The air will drive pistons 49a, 40b and the lead end of the piston rod 41 to the position shown in FIG. 9a. As piston 4% moves forward, the air before it vents through line 49C, the valve chest and line 57 and hydraulic fluid is displaced from piston chamber 42 and forced through line 52 into the header piston cham` ber 14. This fluid transfer will move the header piston 15 and retract the mandrel relative to the anvil as shown in FIG'. 9a. During this movement of the header piston, the meshing engagement of the spur gear 29 with the drive gear 54 is maintained at all times Vwithout regard to the position of the header pitson during the retracting CII stroke. Upon releasing the trigger 55 the valve 48 will close the air passage to line 49u and will open a passage from the valve chest through line 49C to the chamber at the return side of piston 4011 thereby causing the pneumatic power system and the header piston to return to rest (i.e., the position of FIG. 9); air in the chambers 38a and/ or 38b Venting through the valve chest and line S7.

Rotational movements of the mandrel (clockwise and counter-clockwise) are controlled by a conventional air motor, its associated air supply system and appropriate gearing. The rotary air motor is positioned in a separate compartment at the top central portion C of the tool housing above the pistol grip. As shown in FIG. 9, the air motor comprises a bladed rotor 58 mounted on a shaft 59 carrying a spindle gear 60. The rotor shaft 59 is supported by a pair of ball bearings 61, 62 mounted in the end plates 63, 64 of the air motor assembly. The spindle gear 60 drives the planetary gear train 65, 66 which reduces the rotational speed of a ball bearing supported drive gear 54.

Air is supplied to the air motor through a system of internal air passages some of which can be seen schematically in FIG. l and some of which can be seen in FIG. 9. The primary air supply 51 is connected through hose 67' to a tting 68 at the bottom of the pistol grip. A spring loaded trigger controlled cut-ot valve 69 is positioned across the air supply passage 76. The spring loading returns and maintains the valve in a closed position. From the cut-off valve, the air enters a reversing valve 71 Where it can be directed into either of passageways 72a, 72b leading to the air motor; when air goes through one of said passages the rotor will be driven clockwise and when air goes through the other of said passages, the rotor will be driven counter-clockwise. The air motor vents through ports 72C (see FIG. l) in the side of the tool housing.

The power driver can be used to install various sizes of press nuts in the steps illustrated in FIGS. 2 through 8. By pressing trigger 73, the air motor is actuated and the mandrel can be threaded onto the nut. Pressing trigger 55 actuates pneumatic piston and hydraulic power systems and thereby retracts the mandrel relative to the anvil causing a nut threaded on the mandrel to swage and seat the knurl ilush to the sheet.

To change the gun over to a new grip length so as to accommodate nuts wherein the internal recess 8 is positioned to permit installation in work pieces of different thickness, it is merely necessary to reset the anvil relative to the nose nut 35. The preferred positioning is to have from 1 to 3 threads of the mandrel project beyond the nut and then the anvil should be screwed relative to the nose nut until the knurl of the nut is snug against the anvil as shown in FIG. 3.

To change the gun over to permit use of a mandrel to accommodate a nut of different size, the nose nut 35 is held stationary, the anvil 1 is unscrewed; the nose nut 35 is then unscrewed from the header housing 13; the retainer nut 32 is removed from the header piston; the mandrel 2 is removed; the desired size mandrel is inserted and checked for proper engagement with the clutch face on the drive shaft; the retainer nut 32 is installed, the nose nut 35 is replaced and the anvil 1 is reset for the desired grip length.

A unique feature of the tool is that the various pneumatic and hydraulic pistons can be sized so that an easily manipulatable tool will convert compressed air of common operating pressures, eg., less than p.s.i. into a pull with a force of several tons; furthermore this force can be easily varied to suit the requirements of a range of nut sizes. In addition, this pull can be accompanied by rotational motion in either direction, or the pull may be exerted without rotation if the operator so desires. The entire tool is compact and light weight. Another feature of the tool is that its weight is well balanced tore and aft the pistol handgrip. Its operating valves are placed within easy access of the fingers of the hand holding the gun and the tool design is such that right and left handed operators can Vuse the same tool.

The tool employs a conventional air supply system, as shown in FIG. 1, a single source of air is employed to drive both the pneumatic power systems. Air at a suitable pressure, e.g., about 80-100 p.s.i. enters the primary supply line 5l and passes through an air lilter 74. A portion of the air is fed through line 67 to supply the air for air motor, another portion of the .air from the filter goes through pressure regulator 75 since dilierent pressures will be needed for nuts of dilerent diameters is led to a lubricator 76 and then through line 47 to supply the air to the pneumatic piston air supply system.

I claim:

1. A power hand tool assembly for installing press nuts and the like, including a mandrel having an outer threaded end for receiving the internally threaded nut;

an anvil surrounding sand mandrel;

a iirst power system comprising a reversible air motor adapted to controllably impart rotation to the mandrel in clockwise and counter-clockwise directions;

a second power system independent of said iirst power system and including at least one axially movable pressure responsive piston for retracting the mandrel relative to the anvil;

a pneumatic pressure source for driving said first and second power systems;

a rst conduit between said source and said irst power system;

a second conduit between the source and the second power system; and

pressure regulator means in the second conduit for independently varying the pressure supplied to said second power system.

2. A power hand tool according to claim 1 wherein said second power system includes a substantially cylindrical space, at least one transverse wall separating the space into a plurality of axially aligned chambers;

a rod extending through said dividing wall;

a piston mounted on said rod in each of said chambers and having a cross section conforming to the cross section of said chambers;

selector valve means for selectively directing air under pressure to selected numbers of said chambers;

and drive means interconnecting said piston rod and said mandrel for withdrawing said mandrel relative to said anvil.

3. Apparatus according to claim 1 further including a housing having a pistol grip, said housing encasing said rst and second power systems;

a nose nut threadedly secured in said casing;

said anvil being mounted in said nose nut;

a retainer nut mounted on said mandrel inwardly of the anvil for retaining the mandrel in drive position within the casing;

said retainer nut being releasably secured within said housing whereby a change of mandrels may be effected by removal of the nose nut and the retainer nut.

4. A power hand tool assembly for installing internally threaded press nuts and the like comprising:

a housing having a front portion, a rear port-ion and a pistol grip type handle projecting downwardly from and mounted at the center of gravity of said portions;

a mandrel having an externally threaded outer end portion for receiving an internally threaded nut, said mandrel projecting outwardly of the front portion of the housing;

a collar having an anvil port-ion surrounding said mandrel, said collar being threaded to the front portion of the housing and adapted to bear against the head of a nut threaded on said mandrel, said mandrel being capable of axial movement with respect to said anvil, the extent of such relative axial movement being controllable by the setting of the collar with respect to the housing;

a rst power system for imparting rotary motion to the mandrel, said system including a reversible rotary air motor mounted within said housing, drive means including a pair of intermeshing gears interconnecting said air motor and said mandrel, one of said gears being elongated, so that upon relative axial movement of the mandrel with respect to the housing, said gears remain enmeshed;

second power system for imparting axial movement to said mandrel, said system including a plurality of coaxially aligned pneumatic pressure chambers in the rear housing portion;

plurality of pressure responsive pneumatic pistons `fitted within said chambers and mounted on a common piston rod for axial sliding movement upon pressurization of at least one of said chambers, the Vfree end piston rod extending into the housing forming a lirst hydraulic piston head of a hydraulic pressure system adapted to retract the mandrel axially relative to the housing, said hydraulic system including first and second interconnected hydraulic piston chambers, said lirst hydraulic piston chamber adapted to receive the free end of the piston rod driven by the pneumatic piston assembly, said second hydraulic piston chamber being positioned in the front housing portion and having a second hydraulic piston head adapted for axial sliding movement within the second hydraulic chamber upon pressurization of one or more of said pneumatic piston pressure chambers, said second hydraulic piston head being connected to the mandrel and mounted to impart axial movement to the mandrel upon axial movements of the second hydraulic piston head within its chamber, said connection permitting rotational movement of the mandrel with respect to, and independent of, the second hydraulic piston head and without regard to the axial portion of the mandrel relative to the housing and also permitting axial movements of the mandrel with respect to and independent of rotational movements of the mandrel;

a first pressure system including a tirst pressure line cona iirst depressible trigger member mounted on the forward edge of the pistol grip handle and positioned so as to be actuatable by a linger of the holding hand when the handle is held by either the left or right hand, said iirst trigger being connected to a first cutoff valve, spring biasing means urging said iirst cutofi valve into position to block said tirst pressure line, said valve being movable, upon depression of the trigger, out of pressure blocking position in said line;

a second pressure system including a source of air under pressure, a pressure regulator and, a pressure indicator connected thereto and adjustable for maintaining the pressure in a second line serving the housing at a predetermined level;

a plurality of conduits connecting the second pressure line to the pneumatic pressure chambers of said second power system;

a selector valve in said second pressure line; said selector valve being adjustable to selectively connect one or more of said pneumatic piston chambers with the second pressure line and;

a second depressible trigger member mounted on the forward edge of the pistol grip handle and positioned so as to be actuatable by a linger of the holding hand when held by either the left or right hand;

said second trigger having a second cut-off valve member connected thereto, spring biasing means urging said valve into position to block said second pressure line, said valve being movable upon depression of the trigger.

References Cited bythe Examiner UNITED STATES PATENTS 2,445,067 7/48 Hiler 218-47 X 2,723,777 11/55 Amtsberg 218-47 X 2,789,619 4/57 Wing 218-47 X 2,983,256 5/61 Seeloi 92-151 X 3,082,898 3/63 Bosch 218-47 GRANVILLE Y. CUSTER, JR, Primary Examz'er. 

1. A POWER HAND TOOL ASSEMBLY FOR INSTALLING PRESS NUTS AND THE LIKE, INCLUDING A MANDREL HAVING AN OUTER THREADED END FOR RECEIVING THE INTERNALLY THREADED NUT; AN ANVIL SURROUNDINGS SAND MANDREL; A FIRST POWER SYSTEM COMPRISING A REVERSIBLE AIR MOTOR ADAPTED TO CONTROLLABLY IMPART ROTATION TO THE MANDREL IN CLOCKWISE AND COUNTER-CLOCKWISE DIRECTIONS; A SECOND POWER SYSTEM INDEPENDENT OF SAID FIRST POWER SYSTEM AND INCLUDING AT LEAST ONE AXIALLY MOVABLE PRESSURE RESPONSIVE PISTON FOR RETRACTING THE MANDREL RELATIVE TO THE ANVIL; A PNEUMATIC PRESSURE SOURCE FOR DRIVING SAID FIRST AND SECOND POWER SYSTEMS; A FIRST CONDUIT BETWEEN SAID SOURCE AND SAID FIRST POWER SYSTEM; A SECOND CONDUIT BETWEEN THE SOURCE AND THE SECOND POWER SYSTEM; AND PRESSURE REGULATOR MEANS IN THE SECOND CONDUIT FOR INDEPENDENTLY VARYING THE PRESSURE SUPPLIED TO SAID SECOND POWER SYSTEM. 